Groundwater bodies delineation in France .. Susanne Schomburgk BRGM, Water Devision s.schomburgk@brgm.fr Sarah Bonneville MEDDTL, DEB sarah.bonneville@ developpement-durable.gouv.fr
Groundwater bodies delineation 574 GWB 533 in metropolitan France (23 transboundaries) 38 in overseas territories Distribution of GWB types a very heterogeneous geology
Ranges of superposition for a GWB Within an aquifer or aquifers, a distinct volume of groundwater should be described by a three-dimensional groundwater body. Two sedimentary basins in France : - The basin of Paris in the North of France - The Aquitanious basin in the SW of France (example on the left, 15-layer geological model)
Case study of the Aquitanous basin : MONA (MOdèle Nord Aquitain) • Périgueux • Bordeaux • Bergerac • Arcachon • Marmande • Montauban Plio-Quaternaire Langhien-Serravalien Aquitanien Oligocène Éocène supérieur Éocène moyen Éocène inférieur Campanien-Maastrichien Coniacien-Santonien Turonien Cénomanien Tithonien Kimméridgien Bathonien-Callovo-Oxfordien Bajocien Service Géologique Régional Aquitaine
The Groundwater bodies with their superposition
Ranges of superposition for a GWB The approach in France 1 GWB is described by 1 to n polygons Up to 10 ranges No vertical scale : the vertical range doesn’t depend on the depth